1. Field of the Invention
The present invention relates generally to applying microwaves to a material, and more particularly, to a flexible microwave array that can conform closely to complex curvatures of the human body for uniform heat treatment of superficially located tumors or benign skin conditions.
2. Description of the Prior Art
The use of microwave applicators for hyperthermia treatment of superficial tumors is well known. However, difficulties have been encountered in applying such devices to large areas with complex curvatures, such as in the neck and chest area, since the patients must, while retaining the antenna(s) of the microwave applicator in an evenly spaced perpendicular alignment with the surface of the skin, maintain proper inter-antenna spacing in order to facilitate uniform heat treatment. Generally, these microwave applicators are capable of heating areas of superficial tissue for treatment of skin and superficial tissue related diseases such as chestwall recurrence of breast carcinoma, psoriasis or other non-cancerous skin conditions that can benefit from tissue reoxygenation, or increased blood perfusion and blood vessel permeability.
Hyperthermia, which consists of heating tumors at a temperature of 42-45.infin. C for about one hour, has been shown capable of enhancing the affects of common anti-cancer treatments such as radiotherapy and chemotherapy. Effective heat treatment for superficial disease requires an applicator capable of treating irregularly shaped and often widespread disease extending from the skin surface to a maximum depth of about 1 cm. While previously used microwave applicators operating at either 915 or 433 MHz have demonstrated appropriate penetration of Specific Absorption Rate (SAR) for generating effective heating down to a maximum depth of 1-1.5 cm, treatment of the entire lateral extent of disease is usually impossible due to limited applicator size and poor coupling of the rigid planar structures of previous microwave applicators to the skin surface. Because superficial tissue disease often wraps around complex body contours, the applicator must be thin and flexible for complete, closely conforming coverage of various-sized areas as well as lightweight for patient comfort during long treatments.
Thus, previous microwave applicators generally have been inadequate for treating many types of superficial tumors, such as chestwall recurrence of breast carcinoma, skin cancer, psoriasis, and other skin conditions, due to their large, bulky size as well as their generally inflexible, planar arrangement.